The spraying of agricultural chemicals in orchards and vineyards utilizing vehicle mounted air blast sprayers is now a long standing practice. Such air blast sprayers use large volumes of high pressure air, require larger tractors and often, if not universally, disperse excessive quantities of agricultural chemicals. Typically, conventional sprayers can only cover one row at a time. Moreover, prior sprayers are not suited for concurrently applying chemicals to two or more rows of crops when the crops are on sloping ground or terraced land.
My U.S. Pat. No. 5,921,019 issued Jul. 13, 1999 discloses and claims a spraying machine which includes at least a pair of curved arms carrying a plurality of fan spray heads. The spray heads are positioned to direct airborne spray material into the canopy of each tree or vine in upward and downward directions simultaneously from both sides of the canopy. While the method and apparatus of my prior patent has enjoyed commercial success and is a very positive advance over the prior art, it was:
Relatively expensive to produce a suitable structural frame to support the spray arms; PA0 Five fan spray heads per vine row is required when travelling at high ground speed; PA0 Generally suitable for large tractor, crop field and large and dense vine canopies; PA0 Not well suited for terraced crops; and, PA0 Can be difficult to transport to a crop field to be sprayed.